Train stop system



Se t.-27, 1932. HUDD 1,879,617

' TRAIN STOP SYSTEM Original Filed July 11, 1929 4 Sheets-Sheet l I I all,

Sept 27", 1932- A. E. HUDD 1,879,617

TRAIN STOP SYSTEM Original Filed July '11, 1929 4 Sheets-Sheet 2 Sept. 27, 1932. A. E. HUDD TRAINSTOP SYSTEM Original Filed July 11, 1929 4 Sheets-Sheet 3 Sept; 27, 1932. E. HUDD TRAIN STOP SYSTEM Original Filed July 11, 1929 4 Sheets-Sheet 4 Inu Enlar- FIN Ed E. Hu dd 7 Patented Sept. 27, 1932 UNITED STATES PATENT OFFICE ALFRED E. HUDI), OF SUSSEX, ENGLAND, ASSIGNOR, BY MESNE ASSIGNMENTS, TO

ASSOCIATED ELECTRIC LABORATORIES, INC., OF'CHICAGO, ILLINQIS, A CORPORA- 'IION OF DELAWARE TRAIN s'ror SYSTEM Original application filed July 11, 1929, Serial No. 377,418; Divided and this application filed May 26,

1930. Serial No. 455,512. r

The present invention relates in general to train stop systems, but is particularly concerned with the provision of trackway elements and their arrangementfor use in conjunction with a train stop system of the intermittent magnetic inductive type, and is a division of the copending Hudd application, Serial No. 377,418, filed July 11, 1929.

Among the objects of the invention are: to provide improved types of trackway magnets for use in an intermittent inductive cab signal or train stop systems; to provide novel circuit arrangements for controlling the condition of certain of the trackway magnets in accordance with trailic conditions; and .to provide a system which may be readilyused to give protection in single as well as double track systems.

The invention is disclosed in four sheets of drawings: Sheet- 1, comprising Figs. 1 3, shows a section of'trackway equipped with the three types of trackway magnets used and the details of their construction.

Sheet 2, comprising Fig. 4, diagrammatically discloses the vehicle equipment used, and its relation to the trackwayt Sheets 3 and 4, when arranged with sheet a to the right of sheet 3, show two track circuit arrangements; the one comprising Figs. 5 and 5A, and the other comprising Figs. 6

and 6A.

Referring now to Figs. 1-3, the constructional details of the traekway magnet assemblies A, B, and O Willbe described. The trackway magnet assembly'A comprises two soft angle irons 12 and12 hold together by a shallow non-magnetic channel member 25, which is similar to the channel member 25 shown in Fig. 3, and is held in place with rivets such as 26. On the platform supported 33/ the channel member25 two notched wooden members 21' and 21 are placed up against the respective angle-irons 12 and 12 The members 21 and 21 serve as separators for a number of permanent magnets 19. These magnets and the wooden members are held in place on the platform by a non-magnetic cover 16 which is bolted to the channel member 25 with a number of bolts 22. The assembly is held in place on the railroad tie 24, midway between the track rails, by lag screws 13' and 13 To afiord further protection to the assembly a non-magnetic doubly inclinedcover 17 is placed over the assembly and secured to the adjacent ties 23 and 24: by lag screw 1818 The space between the respective magnets 19 allows room for possible warping of the magnets, and also prevents their losing their strength by the tendency of the stronger one to reduce to the power of the weaker one when in direct contact with each other. I This is also the reason for providing a space between the ends of the magnets and. the pole pieces 12 and 12 The trackway magnet C is substantially like A, except that: the angle-irons 12 and 12 are longer; are farther separated by the channel member 25'; and have, at each side of the permanent magnet assembly electromagnets 28 and 29. The wooden members corresponding to 21 and 21 also hold the permanent magnets a greater distance from the pole-pieces 12 and 12*. Due to the additional width of this assembly it is mounted on two ties, and is covered with a somewhat larger cover 17.

The reason for providing a greater space between the ends of the'permanent magnets of the assembly C, than is provided in the device A, isto enable the magnetic field set up by the permanent magnets of assembly C to be rendered ineffective by an extremely low current flow through the associated electromagnets 28 and 29.

The trackway magnet assembly B comprises two angle-iron pole pieces 12 and 12 like the correspondin parts 01" the assembly C. The assembly B, however, does not contain any permanent magnets, but instead, is provided with two pairs of electromagnets 27 and 28', respectively, connecting the pole pieces 12 and 12 through the medium of a. third pole 30. The assembly is provided with a protecting cover 17 substantially like the protecting covers of the assemblies A and C.

existing on the locomotive,but are here shown merely to complete the disclosure of the system. The electro-pneumatic valve EPV, is of the usual type used in automatic train control systems, its main essential being that upon deenergization it permits the exhaust of air through its whistle W. For the purpose of reproducing the wayside signals in the cab, a panel 51 containing lamps G, Y, and R is provided. A terminal box is associated in the cab in the vicinity of the engineers brake valve, and contains terminals for making the necessary connections between the generator, the cab signals, and the electropneumatic valve. This terminal box also contains a switch controlled by an acknowledging button AB, and a light control relay LCR, the functions of which will be described hereinafter. The cab-equipment,

having wires leading into the terminal box 50, 'is connected with the pickup or receiver relay R, through the medium of a junction box J B, located at an appropriate place between the engine and the tender. The automatic brake valve ABV may be of the same general type as the one disclosed in the Hudd application, Serial No. 296,652, filed August 1,

1928, and is designed to cause an automatic brake application to occur a predetermined period after the deenergization of an associated electro-pneumatic valve.

Referring now to Figs. 5 and5A, with .Fig. 5A placed to the right of Fig. 5, the

track circuits shown therein, and the influ- -ence thereon by the presence of the vehicles V and V will be described. In block G the vehicle V is shunting track battery TB from .its track relay T and this relay is consequently in its deenergized condition. The :relay T at its inner and middle armatures has broken the circuit of line relays L1 and L2 and at its outer armature has completed a circuit for the lamp R of the signal S This circuit extends from the positive terminal of the battery GB, through the contact and armature of the line relay L1 the lower armature and lower contact of the track relay T through the lamp R of the signal S to the negative terminal of the battery GB. Neither of the relays Y or G is energized at.this time for a reason which will appear later, and, consequently, there is no 1 current flow in either of the trackway devices C or B 'block G, therefore, will have its train control equipment influenced by the permanent mag- A train approaching the trance end of block F, the influence of the vehicle V on this equipment will be considered. It will be noted that the line relay L2 is deenergized. This occurred when the vehicle V interrupted the circuit of L2 by the associated relay Y and the associated relay dropping the track relay T upon entering the block F, and has remained deenergized,-

because a second point in its circuit was opened when the vehicle V entered the block G, the circuit for relay L2 including in series, the line relay L1 and an armature of T The circuit of these relays extends from the positive terminal of line battery LE through the upper armature and contact of the track relay T the line relay L1 the line conductor 201 through the middle armature and contact of the track relay T the winding of the line relay L2 and the conductor 202 to the negative terminal of the line battery LE The line relay L2 at its armature opens a point in the operating circuit of lamp G of the signal S and of the associated relay G and closes a point in the operating circuit of the lamp Y of the signal S and of The circuit to the relay Y and the lamp Y of S is not closed at this time, however, owing to the energized condition of the line relay L1 this relay being energized over a circuit similar to the one traced through line relays L2 and L1 There is no current flow through the trackway element C or through the element B owing to the deenergized condition of both r lays Y and G and, accordingly, the trackway devices at the exit of block E are for the time caused the deenergization of line relay L1,

thereby causing the lamp G of the signal S to be energized. The circuit for the lamp G of signal S and relay G extends from the positive terminal of battery EB through the contact and armature of relay L1, the lower armature of relay T, and its upper contact, the armature and upper contact of relay LQ, through the lamp G of signal S and relay G in multiple to the negative terminal of the battery EB. The relay G, at its lower armature has completed a circuit through the windings of the trackway device C, and at its middle and upper armatures has completed a circuit through the windings of the trackway magnet B. The circuit through the trackway magnet G extends from the positive terminal of the battery 1313, through the lower contact and armature of relay G, the conductor 204, the windings of the magnet C, the conductor 205, and back 'to the negative terminal of the battery EB.

Owing to the current flow through the electromagnet of the device C, the magnetic field normally set up by the permanent magnets associated therewith is rendered ineffective.

The circuit for the trackway magnet B extends from the positive terminal of the battery EB, through the middle armature and contact of the relay G, conductor 206" the upper and lower windings of B, conductor 207, and through the upper contact and armature of relay G to the negative terminal of the battery EB. The direction of current flow through the windings of B is such that its upper and lower pole-pieces are of north polarity, whereas the middle pole is of south polarity, thereby setting up two magnetic fields, one from the upper to the middle and the other from the lower to the middle polepiece of the trackway device B.

The condition of the vehicle equipment shown in Fig. 4 will now be described, after which it will be assumed that this equipment is on the vehicle V which is travelling toward the vehicle V The vehicle equipment is in the condition which it assumes upon passing a signal at clear; The armatures 125125* are all attracted against their inner polepieces, and, because of this, circuits exist for the cab signal G, the light control relay LCR, and the electro-pneumatic valve EPV, respectively.

The circuit of cab signal G extends from the negative terminal of the generator GEN, through the upper fuse of fuse-box FB, conductor 71, terminal 9 of terminal box 50, jumper to terminal 8, jumper 87 to terminal 5, the conductor 78, lamp G, conductor 77, terminal 4, conductor 63, terminal 4 of junction-box J B, conductor 56, the inner contact and armature 125 conductor 86, armature 125 and its inner contact, conductor 54, terminal 1 of JB, the detector loop,'terminal 2 of J B, conductor 61, terminal 2 of 50, conductor 74., the acknowledging switch. c0nductor 73, terminal 1, the lower fuse of fusebox FB to the positive terminal of the generator GEN.

The winding 52 of the light control relay LCR, by means of the conductors80 and 81, is connected in multiple with the lamp G and is, therefore, energized whenever a circuit exists for the lamp.

The circuit for the electro-pneumatic valve EPV extends from negative potential on terminal 9 of 50, over conductor 70. through EPV, conductor 68,terminal 12 of 50, jumper 67. terminal 11, conductor 66, terminal 5 of JB. conductor 60, armature 125' and its inner contact, inner contact and armature 125 conductor 57, to positive generator supplied to the terminal 1 of JB by way of the detector loop, terminal 2 the conductor 61, terminal 2 of 50, and the acknowledging switch. It may be well to call attention to the fact that all apparatus on the vehicle must obtain the positive current through the acknowledging switch and through the detector loop, respectively, and, therefore, if the detector loop be comes broken an automatic brake application will take place. I v

The effect on the vehicle equipment, as the vehicle V advances will now be explained.

Since, as previously mentioned, the trackway element C has its electromagnet winding energized at this time, the permanent magnets thereof are rendered ineffective to influence the armatures of the receiver R north pole, and collector plates 102 and 102 are brought into the inductive field of the south pole of the trackway device A. Since the armatures 125 and 125* are already of north polarity, because of the presence of the associated polarizing magnets 84 and 84, there will be no tendency for these armatures to move. The armatures 125 and 125", also of north polarity, because of the presence of polarizing magnets 84 and 84?, will, however, be attracted to their outer pole pieces, because of the attractive effect produced therein by the magnetic flux picked up by the collector plates 102 and 102 from the south pole of the magnets of the trackway device.

A. After the receiver passes out of the inductive field of the trackway device A the armatures 125 and 125 Vremain in their operated position owing to the natural attraction of the armature to the nearest pole piece, because of the presence of the polarizing magnets 84 and 84 The armature 125 in operating, opens the traced circuit for the lamp G and relay LCR, causing that lamp to be extinguished, and the relay to drop its armature. The armature'125 in operating, opens the traced circuit of the electro-pneumatic valve EPV which becomes deenergized andpermits air to exhaust through the whistle W'; and at its 7 lower contact closes a point in the circuit of lamp Y, which will be traced later. The dropping of the armature of relay LCR prepares a point in the circuit of lamp R, which will also be traced later.

The opening through the whistle W is of such a size that approximately six seconds ill) must elapse before sufiicient air has passed 7 therethrough to permit the operation of the automatic brake valve ABV. Before much of this time expires, however, the receiver R in the vehicleV passes through the inductive field of the trackway device B, which, as previously explained, is so energized that its upper and lower pole pieces are of north 3 polarity, whereas its center pole piece is of south polarity. As the receiver R passes through the magnetic field set up by the trackway device B the collector plates 102,

102*, 102 and 102 collect magnetic flux of north polarity from the upper and lower pole pieces of B, while the collector plates 102 and 102 collect magnetic flux of south polarity from the middle pole-piece of B. H

The magnetism induced in the pole pieces of collector plat-es 102 and 102 being of the same polarity as that normally existing in armatures 125 and 125 because ofthe pres ence of the polarizing magnets, tends to make the armatures remain in engagement with their inner pole-pieces, While the magnetic flux induced in the pole-pieces of collector plates 102 and 102 is of south polarity. This causes all armatures 125125 to tend to be drawn towards their inner pole-pieces; while in the case of the collector plates 102 and 102, since the magnetic flux induced therein is of north polarity, the pole-pieces of these collector plates tend to oppose or push away the armatures 125 and 125 with the result that these arniatures are restored to their initial position, causing the circuits for lamp G, the winding 52 of relay LCR and valve EPV to be reestablished automatically. The momentary operation of the Whistle lV and the momentary extinguishing of lamp Gr simply serve to inform the enginemen that they have passed a signal at clear.

As the vehicle V enters the block E, the track relay T is shunted out by the axle of the vehicle, and accordingly, drops its armature. As in the case of the track relay T the track relay T at its upper armature interrupts a second point in the circuit or" line relay Ll preventing that relay from becoming reenergized until the vehicle V is clear of the block E; at its middle armature it interrupts the circuit of line relays L2 and L1 and at its lower armature it interrupts the multiple circuit of the lamp G of signal S and of relay G, and closes a circuit for the lamp R of signal S. The circuit of the red lamp R of signal S extends from the positive terminal of the battery EB, through the contact and armature of L, the lower armature and lower contact of T, through the lamp R, conductor 203, and back to the negative terminal of battery EB.

The dropping of the armature of relay L1 when the vehicle V enters block E com- 'pletes a circuit for the lamp Y of signal S This circuit extends from the positive terminal of the battery FB, through the contact and armature of L1 the lower armature and upper contact of track relay T2, the armature and lower contact of L2 and through the .rela Y and lamp Y of si 'nal S in multi ale L b l through the trackway device B extending from the positive terminal of the battery FB, through its middle armature and contact, the conductor 207 and through the lower and upper windings, respectively, of the trackway device E the conductor 206 and the upper contact and armature to the negative terminal of the battery FB. It should be noted at this time that the current flow through the trackway device 13 is in the direction reverse to that in which current passed through the trackway device B while the vehicle V was passing thereover.

As the vehicle V passes over the trackway magnets A the armatures 12- 2 and 125 of the receiver R are operated, as in the case when the receiver passed over the trackway device A, again positioning armatures 125 and 125 against their outside pole-pieces. An instant later, as the receiver passes over the trackway device B the armatur-es 125 and 125 are also moved into engagement with their outside pole-pieces. This occurs,

because the polarity of the upper and lower simply interrupts a second point in the circuit of the electro-pneumatic valve EPV, while the armature 125 in addition to opening a second point in the circuit of the cab signal lamp at its upper contact. completes a circuit for the cab signal lamp Y andv tor the winding 52 of relay LCR. The lighting up otlamp Y and the continuous o eration of the whistle W serves to inform the en s neman that a signal has been passed at cauti on and acknowledgment must immediately be made to prevent the occurrence of a automatic brake appl cation. The circuit for he cab signal lam Y ext nds from the ne ati e terminal of the generator GEN. over the previously traced c rcuit to conductor 78. through the lamp Y. terminal 7 of term nal box 50. terminal '7 oi iunction ho: .TB. cond ctor the lower contact and armature 125 conductor 86, armature 125 and its upper contact. conduc or 55, terminal 1 of the junction box JB, the detector loop, and over the previously traced circuit to the positive terminal of the generator. A branch circuit. in multiple with that traced for the lamp Y, extends from terminal of the termi nal box 50. through the winding 52 of relay LCR, and back to the negative terminal of the generator by way of terminal 9, and maintains the relay LCR energized when the lamp Y is lighted.

takes place. To acknowledge, an engine man simply momentarily depresses the'gacknowledging button AB. While the acknowledging button is depressed, positive current is removed from conductor 7 i, thereby extinguishing lamp Y deenergizing relay the receivercomes into the inductive field of LOB, and opening a second point in the circuit of EPV. The button AB must, there fore, be restored to bring about the reenergizaation of the electro-pneumatic valve EPV.

The pressing of the acknowledging button" causes a circuit to be completed for restoring armatures 125 and 125 into engagement with their inner pole pieces. lhis circuit extends from the negative terminal of the generator, over the previously traced path to terminal 8 in the terminal-box 50, conductor 65, terminal 6 in junction box JB, conductor 58, through the armature restoring windings 88 and 88 in series, conductor 59, terminal 3 of J B, conductor 62, the terminal 3 of the terminal box 50, the conductor 75,

the acknowledging switch to the conductor 73 and positive generator. The current flow through the windings 88 and 88 causes the pole-pieces thereof to attract the armatures 125 and 125 back into their normal position. Upon the restoration of the acknowledging. button AB the previously traced circuits for tl e lamp Y, relay LCR, and electro-pneumatic valve EPV are again reestablished. It will be noted that there is noman'uallycom trolled means for actuating the armatures 125 and 125 and, therefore, the only way oi changing the lamp signal indication in the cab is by picking up influences from the trackwa i is the vehicle V enters into block F the track relay T is shunted out and, accord= ingly, drops its armatures. This relay at its lower armature opens the circuit of lamp Y of signal S and completes, the circuit of the,

lamo R of si nal S at its u erarmature I l b pp control opens a second point in the circuit of linerelays L1 and L2 and at its middle armature opens a second point in the circuit'of relays L2 and L1 As the vehicle V clears: the block E the track relay T again becomes energized; at

its upper armature again completes the oper ating circuit of line relay L1, at its middle armature closes a point in the circuit of line relays L2 and L1 and at its lower arma ture interrupts the circuit of lamp R of signal S and prepares a circuit for the lamp Y of signal S. The energization of line relay Ll,

however, prevents the lighting up of lamp, Y

of signal S until a vehicleenters the block D, as previously described. Sincethelamp R of the signal S is li hted, lamps Y and G of S and relays Y and sequently, as previously brought out, there 1 tending from the Gr are deenergized. Gonis now no current flow through the electro, magnets of the trackway devices C and B Attentionis now called to the fact, that as. the receiver R is approachingthe trackway device C ,.with the yellow lamp Y in the cab lighted, its armatures 125 and armature 125 are in their normal position, as shown, while the armatures 12b? and 125* are both in engagement with their outside pole pieces. As

the trackway device G which has its electromagnet deenergized atthis time, the inductor C functions in the same manner as a perma nent magnet trackway device such as A, A or accordingly, the north polarity induced into the collector plate 102 causes the armature 125 to be repelled and moved into engagement with its inner pole-piece, thereby interrupting the traced circuits of lamp Y and relay LGR and completing a circuit for cab signal It, while the south polarity induced in the pole-piece oi the collector plate 102 attracts the armature 125 to its outside pole piece, to again initiate a brake-application by interrupting the traced circuit for the electropneumatic valve. To avoid an automatic brake application an engineman must again acknowledge to restore the armature12h in the manner formerly described. Upon the restoration of the armature 125 a circuit for the lamp R in the vehicle cab in multiple with r the circuit of the electro-pneumatic valve EPV is completed. This circuit extends from the negative terminal of the generator GEN overthe circuit traced to conductor 78,

through'the lamp R, conductor 79, the terminal 10 in the terminal box 50, the back contact and armature of relay LCR, the conductor 69,130 the terminal12 of the terminal box 50 where it joins the traced circuit expositive side of the-generator.

The lighted lamp R in the vehicle cab advises the enginemen that they have arrived within braking distance of an occupied block and must, therefore, have the vehicle in full prepared to stop at the entrance to block G. r 7

When the receiver R passes over the trackway device A the armature 125 is again actuated to again initiate a brake application. Since at this timethere is no current fio'w through the trackway device B an engineman must again acknowledge to prevent an automatic brake application.

If a vehicle enters a block at clear or stop and thenbacks over the Band A inductors of the block justentered the re ceiver will respond to the A inductor, e-Xtin guishtheexisting cab signal, and initiate a 'ment, the lamp R lighted. i

- Referring now to Figs. 6 and 6A, the application of the invention applied to a railway signalling circuit of the wireless type, and special features provided at the entrance to sidings and cross-overs will be described. Thesignal S at the cross-over X in block L is inter-locked with the signal S in the usual manner, and the circuit arrangements are such that when the block L is occupied or -when the signal S is in proceed position the track battery of block L will be shunted from the associated trackrelay T Since in the examplegiven the signal S is in proceed position the track relay T is deenergized. This 3 relay, at its upper and middle neutral armatures .and their lower contacts connects the battery LB across the rails of block K in the proper direction to cause the track relay T at the entrance to that block to moveits polarized armature to the right, but owing to the presence of vehicle V in that block the track relay T is deeuergized. The track relay T at its lower neutral armature interrupts thenormally established circuit extending over conductors 304 305 304 and 305 to the trackway devices 0 and C", respectively, and at its lower neutral-and polarized armature disconnects the battery 113 from the pole changing relay P through the contacts of which, the trackway device B is supplied with current through the lower neutral armature of the track relay T in a direction dependent on the energized and deenergized condition of the pole-changing relay P It will be assumed for the moment that the vehicle V is equipped with the vehicle equipment such as shown in Fig. 4, and further that the vehicle V passes from the block K into block L. As the receiver R passes over the trackway device C (placed at braking "Shortly after the, acknowledgment is made distance from the exit of the block) the vehicle receiver relay armatures will be operated in the same manner as described when passing over the trackway inductor C the receiver will pass over trackway device C and a second acknowledgment will conse quently have to be made. The passing over the permanent magnet trackway inductor A will require a third acknowledgment of the engineman. Thesewarnings come in fairly close succession and serve to inform theenginemen that they are approaching a crossover at which the signal is set at stop, and that they should, therefore, proceed with ex treme'caution. V As previously stated, owing to the presence of vehicle V in block K, the associated track rela y'T is deenergized. This relay, at

its upper two armatures and their lower contacts connects the battery KB across the rails of block J in such a manner that the current flow to the track relay T is energized in the proper direction to cause its polarized armature to swing to the right; at its next to bottom neutral armature opens the circuit of relay 310; and at its lower-most neutral armature completes a circuit for the thermo-relay 320. The relay 310, in dropping its armature, opens a second point in a circuit for the electro-magnetic switch lock 325. After a definite period the thermo relay 320 again closes a circuit for relay 310. This arrangement is provided to prevent the associated siding being electrically unlocked and connected with the main line by operation of button 315 while the section between the siding and the entrance end of block K is occupied, or at least until suihcient time has elapsed to allow the vehicle V to have approached near the vicinity of the siding. The polarized armature of the track relay T serves to open the circuit of the trackway device C to cause it to function in the same manner as did the trackway device C under the same trafiic condition. The track relay T also at its two upper armatures connects the battery KB across the rails of block J in in the proper direction to cause the track relay T to move its polarized armature to the left. The track relay T also, at its lower neutral armature, completes a circuit by way of conductor 305', the battery IE and conductor 304' for the trackway device C rendering the permanent magnets thereof in effective to influence the receiver relay of an approaching vehicle. The relay T also, at its lower neutral armature, completes a circuit from the positive terminal of battery 1B through. the lower contact and armature of the pole changing relay P the conductor 307 the lower and upper windings of the trackway device B conductor 306 the upper armature and lower contact of relay P and back to the negative terminal of the battery 1B The current flow through the trackway device B is in the same direc tion as that traced through the trackway device B and, therefore, will haVe a like influence on the receiver ofa vehicle passing thereover. I

The trackway relay T completes circuits similarto those traced through the contacts of the track relay T except that the relay t ing electromagnets only, the respective assemature of this relay, conductor 308', through the pole-changing relay P, back to the negative terminal of battery IE. lhe pole changing relay P, therefore, changes the di rection of current flow to the traclrway device B", causingit to be energized in the same manner as was the corresponding traclzway device 13 at the exit end of block I).

Since the condition of the trachway vices of blocks H, I, J, and K are identical to pole-pieces, and means for holding said mag-f nets in a definite spaced relation to each other and to the said pole-pieces. V

2. In a trackway device, an electromagnet including a coil surrounding an iron core and having pole-pieces connected at each end thereof at right angles thereto, and also in cluding a set of permanent magnets placed parallel to said core with their ends a sub stantial distance from the pole-pieces of said electromagnet.

3. In a train control system, a trackway divided into insulated block sections; a trackway element at braking distance from the exit end of a block, comprising a set of permanent magnets and an electromagnet; a second trachway element a short distance from the exit end of the block, comprising a set of permanent magnets; and a third element nearer the exit of the block than is the second element and comprising a three-pole electromagnet.

4-. In a train control system, a trackway divided into insulated block sections; a track- Way element at braking distance from the exit end of a block, comprising a set of permanent magnets and an electromagnet; a second trackway element a short distance from the exit end of the block, comprising a set of permanent magnets; a third element nearer the exit of the block than is the second element and comprising, a three-pole elec tromagnet; and vehicle trafiic controlled means for causing the electromagnet of the first and third elements to be energized only when a vehicle passes thereover while tratfic conditions in advance are clear or caution.

5. In an arrangement of trackway elements Eor inductively transmitting influences to a passing vehicle, two assemblies each comprising a set of permanent and electromagnets, a third assembly comprising permanent magnets only, and a fourth assembly compr1s blies being arranged along the trackway in the order named.

6. In a train control system, a trackway divided into block sections; trachway equipment at substantially braking distance from the eXit end of a. block, comprising permanent and electromagnets; trackway equipment a short distance from the exit end of the block, comprising a set of permanent magnets; and other trackway equipment, nearer the exit of the block than is the last mentioned trackway equipment, comprising a three-pole electromagnet.

7. In a train control system, vehicle cab equipment for reproducing signal indications in the cab corresponding to the indications displayed by the approached Wayside signals, a permanent magnet trackway element in eachblock producing a magnetic field traversed by a pick-up relay of the vehicle equipmentand acting thereon to erase any previous signal indication given in the cab, a dual field electromagnet, and means for controlling the magnetic fields of said magnet in accordance with trafiic 'conditions, so that when the same is subsequently encountered by the pick-up relay it acts thereon to reproduce in the cab a signal indication in accordance with that displayed by the wayside signal of the block being entered.

8. In a trackway impulse transmitting system for automatic train control, a permanent magnet placed transverse of the track rails near the exit of a block, a three-pole electromagnet track element placed transverse of the rails still nearer the exit of such block, and means for energizing said electromagnet to produce a magnetic field which is effective to neutralize or modify the efiect on a vehicle produced by the field of the permanent magnet, the effect produced by said electromagnet being determined by the traflic conditions existing at the time the vehicle is influenced by the electromagnet.

In Witness whereof, I hereunto subscribe my name this 8th day of May, A. D. 1930.

ALFRED E. HUDD. 

